Tiltable window assemblies have previously incorporated tilt latches at the end of the window sash opposite the pivot bar of the tilt mechanism. The previous latch mechanisms have generally provided additional mechanical support for maintaining the window sash in a non-tilted position, so as to be oriented in a plane which enables a direction of travel of the window sash within the window frame.
Prior tilt latches have included a bolt, which travels within a latch housing, and which selectively engages the side jamb of the window frame. The bolts generally have an angled surface at the end of the bolt and on the side of the bolt, that engages the side jamb. When the angled surface of the bolt engages the side jamb as the window sash moves from a tilted position to a non-tilted position, the angled surface of the bolt causes the bolt to at least momentarily deflect inward until it clears the obstructing portion of the side jamb.
The other side of the end of the bolt that engages the side jamb as the window sash moves from a non-tilted position to a tilted position, is generally perpendicular to the direction of tilting movement. The generally perpendicular side of the bolt, when it engages the obstructing portion of the side jamb does not deflect the bolt, but engages the side jamb and resists movement toward a tilted position. Generally the sash is rotationally locked in a non-tilted position within the window frame until the end of the bolt of the tilt latch, which is generally biased toward engagement, is manually retracted and released from the side jamb. An early example of such a tilt latch is described in Menns, U.S. Pat. No. 1,862,757.
Window can be subjected to extreme weather conditions, where the required response to the extreme weather conditions are often dictated by building codes. Trends in building codes have increasingly required that the window assemblies be able to survive increasingly extreme weather conditions. One such example includes high winds or large pressure differentials between indoor and outdoor pressures, which can be associated with tornadoes and/or hurricanes. Windows may also be expected to survive an impact from one or more types of flying debris. Examples of different types of materials used to simulate flying debris includes two-by-four pieces of wood and ball bearings to simulate small rocks and/or hail.
Historically, accepted wisdom suggested that one should open the window slightly during a tornado or a hurricane, so as to provide an air path via which the air pressure on the interior side of the window can more easily be equated to the air pressure on the external side of the window. However, more recently, the generally accepted wisdom has changed to suggest, that one should maintain the window in a closed position. This is because storms, which have high winds, like hurricanes, are often accompanied by rain. By opening the window during such a storm, one may be subjecting the interior of the building to potential water damage, where any pressure equalizing effects are now viewed as having only a marginal effect. Additionally, opening the window slightly may affect the structural integrity of the window by disengaging elements, which would otherwise overlap and/or be locked together.
As the building code requirements become increasingly stringent, the building techniques and the components used in the construction of a window assembly need to keep pace or stay ahead of the stricter standards, in order to be able to sell into the markets covered by the building codes. Consequently, there is a need to develop building techniques and/or better components and incorporate them into the window assemblies, in order to enhance the integrity of the window, and allow it to withstand greater and greater harmful forces, as required by the building codes.
Many currently used window assemblies include plastic extruded jamb liners, which can deflect when under relatively high levels of stress. Similarly, the top and bottom rails, as well as the stiles of the window sash for many window assemblies are also made from extruded plastic components, which are then welded together at the joints. The plastic extruded top and bottom rails can similarly bow and/or deflect, when significant external forces are applied.
As the window sash bows and/or deflects, the ends of the top and bottom rails can be deflected away from the side jamb toward the center of the window assembly. This in turn can pull the attached tilt latch assemblies away from and out of engagement with the side jamb. As a result, the tilt latch assemblies may no longer prevent the tilt motion of the window sash. Additionally the tilt latch assemblies may no longer anchor the non-pivot point side of the window sash within the window frame. This then becomes a weak point in the window construction, and a likely point for failure, when extreme forces are applied.
Still further, the flexing of the window assemblies, as a result of and in addition to the high wind forces, can sometimes cause the mounted window hardware to shear away, thereby further affecting the continued integrity of the window assembly. Consequently, it would be beneficial to develop a tilt-latch, which resists becoming detached or torn away from the window sash, and which adds additional support to the window assembly when the window assembly is subjected to higher levels of stress.